Schluter-Systems DITRA-HEAT (120V) Floor Heat Cable, warms 92 sq ft [DHEHK12092] adaptable to any layout, adds comfort to any room, quickly and easily installs into membrane before tile/stone - Amazon.com
Mechanicals-Floor Warming - Northern Built
Schluter Systems 120-Volt Radiant Ditra-Heat-E-HK Warming Wire 32-sq ft in the Underfloor Heating department at Lowes.com